Westpac customers will soon be able to receive instant alerts if their spending in various categories is out of whack with their usual spending behaviour.

The "traffic light" alerts are one of the money-management tools developed by New York-based technology company Moven that will be incorporated into the bank's new internet banking platform from October.

Westpac says the new banking platform will help customers better understand how they are spending money compared with their historical averages. From next year, the Moven technology will provide real-time spending alerts and feedback, combined with tools that help customers decide if they can afford to make a purchase.

Westpac chief digital officer Simon Pomeroy said: "While these tools were developed originally as a mobile app, we are integrating them into our fully responsive internet banking platform meaning customers will be able to use the features from any smartphone and tablet as well as desktop".

"They also complement other features we will be releasing on our new internet banking platform later this year."

Westpac said it was working with Moven towards a platform that would automatically categorise transactions and allow customers to obtain more details such as where, when, and on what device purchases were made.

Customers will receive a mobile receipt for any purchase being made, with the purchase automatically categorised to provide real-time insights into the implications of their spending.

Customers would also be able to see a "traffic light" graph showing their average spend versus their actual spend for a month, Westpac said.

"The key to this set of features is the ease of use," Pomeroy said.

The system comes preloaded with 12 categories, with spending information presented in graphs in real time, he said.